Heat in electronic circuitry if not dissipated sufficiently enough can reduce performance, cause soft errors, and in a worst case—result in catastrophic failure requiring replacement of components. The heat generated by electronic circuitry is a direct function of clock frequency. Temperature, a measure of heat, is proportional to power consumption which in turn is proportional to operational frequency. In order to reduce the temperature of a silicon junction in a processor, heat at the junction needs to be dissipated into the ambient air somehow. With processors now exceeding clock frequencies of one gigaHertz, methods of heat dissipation are even more important.
Various well know methods to dissipate heat in circuitry can be employed. For example passive techniques such as heat slugs, heat spreaders or heat sinks can be employed to increase the heat dissipation from circuitry into the atmosphere. Active techniques, such as an air/fan cooling system or a liquid cooling system can also be used to increase heat dissipation from circuitry.
Generally in integrated circuitry when power consumption is reduced, less heat is generated which needs to be dissipated. In order to conserve power in integrated circuit processors, circuit activity has been analyzed. When circuitry is not active, it is desirable to turn off clocks to the inactive circuitry. It was generally assumed that this would reduce the heat generated. While this may be true over an average, it is not necessarily true instantaneously. In some cases when a clock is abruptly stopped to circuitry, the heat generated actually increases causing the thermal temperature of the integrated circuitry to rise.
It is desirable to improve the thermal management of integrated circuits.
Like reference numbers and designations in the drawings indicate like elements providing similar functionality.